The present invention relates generally to intravenous catheters, and more particularly to an intravenous catheter having a connector operable with a blunt cannula to control the flow of fluid through the IV catheter.
Intravenous (IV) therapy is a versatile technique used for the administration of medical fluids to patients. It has been used for various purposes such as the maintenance of fluid and electrolyte balance, the transfusion of blood, the administration of nutritional supplements, chemotherapy, and the administration of drugs and medications. Fluids may be administered intravenously by injection through a hypodermic syringe, or intermittently or continuously by infusion using a needle or a plastic or silicone catheter.
Although there are many advantages to be derived by the patient from the intravenous administration of fluids, the past two decades have brought heightened awareness of the risks of propagating infectious diseases associated with the technique, particularly due to the HIV virus. One method by which infectious disease may be spread is an inadvertent puncture of medical personnel by the sharp needle that was used to insert an IV catheter into an infected patient. Such needles are extremely sharp and should the insertion site become wet with administration fluid or blood, the medical personnel may inadvertently puncture herself or himself while handling the sharp needle. Any opening in the skin raises the possibility of contracting an infection.
One consequence of this heightened awareness has been the development of various devices designed to reduce the risk of spreading infectious diseases during the IV procedure. Devices have been developed over the years to attempt to lower the risk of such inadvertent punctures. One such class of devices has been the blunt cannula approach to connectors. In this class of connectors, sharp needles are not used. In one approach in this class, the connecting devices have been designed based on the Luer system of connectors in which the mating surfaces are tapered. While this approach has advanced the safety of health care workers substantially, a venipuncture procedure still requires the use of a sharp needle.
Another class of devices developed in the venipuncture area is the safety needle. This is a type of needle housed inside a protective guard. It comprises a sharp needle that may be extended from and retracted into the protective guard, the purpose of which is to lessen the chance of an inadvertent needle puncture of medical personnel. It provides the required sharp needle for the venipuncture procedure but carefully guards the operator against the sharp needle except for the one time it is extended to pierce the patient. In some versions, the sharp needle is locked within the protective guard once it has been retracted. The possibility of an inadvertent puncture is further reduced with such an arrangement.
Catheters used for peripheral IV therapy tend to be relatively short, between 19 mm and 32 mm long, although they are occasionally 50.8 mm long for insertion into a deep vein. A peripheral IV catheter is made of soft, flexible plastic or silicone, generally between 16 gauge and 24 gauge. In the conventional venipuncture procedure, the catheter is inserted into a vein in the patient's hand, foot, or the inner aspect of the arm or any vein in the body that will accept an IV catheter.
IV catheters are used to provide fluid to or to withdraw fluid from a patient. In order to properly place an IV catheter in a patient's vein, a sharp introducer needle must be used to puncture the skin, tissue, and vein wall to provide a path for placement of the catheter in the vein. Typical IV catheters are “over-the needle” catheters where the catheter is coaxially placed over the needle. The catheter thus rides with the needle through the skin, tissue, and vein wall and into the patient's vein. When the needle pierces the vein, blood will “flashback” into the needle. Thus, once the clinician observes this flashback of blood, the clinician will know that the catheter and needle have been inserted in the vein. The needle can then be withdrawn from the patient and the catheter can be advanced further into the vein as desired.
In further detail, a tourniquet is applied proximal to the venipuncture site and a variety of techniques may be used to dilate the vein. While wearing disposable gloves, the medical technician cleanses the venipuncture site and a vein is retracted or anchored by placing a thumb over the vein about 50 mm to 75 mm distal to the site. A catheter with a sharp stylet or needle advanced through its lumen so that the sharp tip extends beyond the cannula of the catheter, or a butterfly needle, is introduced into the vein by inserting the bevel into the vein at about a 20 degree to 30 degree angle with the bevel facing up in order to pierce one wall of the vein. Blood return in the tubing of the butterfly needle or a flashback chamber of the over-the-needle catheter indicates that the vein has been entered, and the needle is lowered towards the skin to decrease the entry angle and the catheter is advanced about 6.35 mm into the vein. The sharp needle or stylet is loosened and the catheter is gently advanced farther up into the vein until the hub of the catheter is against the venipuncture site. The tourniquet is loosened and the sharp needle or stylet is removed from the catheter. The needle adaptor of the infusion tubing is secured to the hub of the catheter, and the roller clamp is opened. The flow rate may be controlled either by adjusting the amount of pressure exerted by the roller clamp or by adjusting the infusion rate of an infusion pump. The catheter is secured to the venipuncture site by gauze and adhesive tape.
During the above venipuncture procedure, medical personnel are exposed to the possibility of an accidental needle puncture or to contamination from the back flow of the patient's blood from the venipuncture site. While care is usually taken to avoid a puncture of the medical personnel, circumstances may arise during which a puncture of the medical personnel may nevertheless occur exposing the health care personnel to any infectious blood borne diseases carried by the patient.
Devices have been developed to reduce the risk of such accidental needle punctures, but a need has been recognized for devices that efficiently prevent the back flow of blood while providing a swabbable female Luer port. In one case, there has been provided an intravenous catheter insertion apparatus that includes a catheter integral with a connector having a pre-slit septum. A blunt cannula is used to penetrate the pre-slit septum and a needle tube having a sharp needle of sufficient length to pass through the blunt cannula, the connector, and the catheter is attached leaving the sharp tip of the needle projecting beyond the end of the catheter. After the catheter has been inserted into the blood vessel of the patient, the needle tube and blunt cannula may be removed from the connector/catheter device and during removal, the septum of the injection site prevents blood from leaking out of the catheter. Also during removal, the sharp needle tip may be withdrawn into the needle tube that provides a guard over the sharp needle tip to protect the medical personnel performing the IV procedure from puncture.
However, a problem that may result from such an assembly using a pre-slit septum in the connector/catheter device is the possibility of damage to the septum due to the blunt cannula being repeatedly forced into the normally closed pre-slit septum. A damaged septum may leak blood and this may then expose a health care provider to any infectious diseases contained in the blood. A further problem that may arise during the use of such an assembly is that some guarded needle devices available today are somewhat complex with multiple stops and locking devices designed to protect the medical personnel from needle punctures. Unfortunately, the action of sliding the needle into the fluid path created by the blunt cannula and the pre-slit septum with these complex devices may require more than one physical hand movement by the medical personnel operating the assembly. Because medical personnel are quite busy, any additional efforts required to accomplish tasks are undesirable. Further, the requirement of extremely fine motor skills during the placement of a sharp needle in a catheter and into a patient can result in inadvertent damage to the connector of the catheter resulting in blood leakage.
Pre-slit septum systems also do not typically allow access to the catheter with standard male Luer connectors. An adapter is required, which is not desirable. In addition to the expense of an additional part, such adapters can get lost or may not be in stock when needed.
Hence, those skilled in the art have recognized a need for a safety catheter insertion device that provides increased protection from needle punctures to medical personnel handling the device. Additionally, a need has been recognized for a more reliable insertion device that is less likely to leak a patient's blood after removal of the catheter needle and even after continued reuse of the device. A further need has been recognized for an insertion device that is easier to use so that less effort, steps, and time are required to accomplish the placement in the patient. And furthermore, an insertion device that is easier to manufacture and that is cost effective is also needed. The present invention satisfies these needs and others.